Art of electrical precipitation of suspended material from gases



Sept. 1,- 1925. v

\ I E. ANDERSON ARTIOFELEOTRICAL PRECIPITATION 0F SUSPENDED MATERIALFROM GASES Filed May 31, 1922 INVENTOR. E'vald flnclerson.

ATTORNEY.

Patented Sept. 1, 1925.

UNIT-ED snares .uvALn ANDERSON, or ALHAMBR cALironNIA', ASSIGNOR mo mmamnu. ram

CIPITATION COMPANY, or nos ANGELES, cAr..Iro1mI-A;A conronArIon o cA I-romu 4 Arm or ELECTRICAL rnEcrn rA'rmN or-susrmmnn am. r301; eA'sns.

Application mm Kay a1, 1922. Serial No. 504,074..

To all whom it may concern:

Be it known that I4, EVALD ANnnnsoia a citizen of United States,residing at A hambra, county of ,Los Angeles, State,of* California, haveinvented a new and useful Improvement in the Art of- ElectricalPreaction, and the main object of the invention is'to provide for suchseparation in a con- J tinuous manner so that the-electricalprecipitating operation proceeds continuously and does not have to beinterrupted for cleaning operations.

In the operation of electrical preci itation apparatus the gasescarrying suspe ed material arepassed between discharge and col.- lectingelectrodes which are, maintained at high electrical potentialdifference, in such manner that the suspended material car-- ried by thegases isdeposited or collected'to a greater or less extent on suchelectrodes; and in the operation of such apparatus it has heretoforegenerally been necessary to shut down the apparatus from timeto time soas to enable the material collected-on the electrodes to'be removedtherefrom. Such shutting down of the'apparatus has -gener-' allyincluded the shutting off of; the gas streamby means of dampers orotherwlse, so as to preventmaterial dislodged from the electrodes in.the cleaning operation. from being carried forward with'the gas streamand from being discharged at the outlet nuisance or loss 0 or stack ofthe a paratus, resulting 'in a cleaning operation as heretoforeconducted, therefore, involves. acessation of the normal operation ofthe .treater, resultin indecreased capacity of the treater'an inconsiderabl'e'expense due to the oversight and control required inconnection with such cleaning operations. I 1

By means of my-invention hereinafter described, the gases are cleanedbyj'passing .them through a series of electrical precipitation zones,each precipitating zone includ- 'ing a set of electrodes, and electrodesinthe successive sets being subjected to cleaning valuable material. The

and supported operation for removing deposited material therefrom .atdifferent times so that at all times the major part of the,precipitatlng 1 an time, the number of sections being suffic'ient toalways provide for effective pre-- cipitation by the operation of thosesections which are not beingcleaned.

The accompanying drawings i llu'strate embodiments of my invention andreferr' means is in operation and the cleaning optheretoz; Fig. 1 is alongitudinal section 0 one form of such apparatus. Fig. 2 is .a

vertical section on line2 -2 of Fig. 1.

3 is a longitudinal section .of another form of such, apparatus. 2 Fig.,4 is asection on line 4-4 in Fig. 3. Fig. 5 is a diagram of a modifiedform of; electrical circuit control.

In Figs. 1 and 2 my invention is shown as applied to an electricalprecipitator of the s'oj-called plate and wire type comprisin collectingelectrodes formed as plates an 7 dischargeelectrodes formed as wires,chains or other flexible members, all arranged in a flue or chamber 1through which the gases are passed, the said electrodes being arrangedin a series of sections for units indi-' cated at 2, it beingunderstood, however,

that any desired number of units or sections may be used provided thenumber 'is sufiiciently great to give the desiredouniformity ofoperation. In general, at least five sections are desirable.Eachfsection 2 includes a set of collecting electrode plates or screens3 and a set of high tension discharge electrodes- 4 arranged inalternation with and opposite to the respective plates. The collectingelectrodes-3 may be suspended from by supporting consisting. of beamsindicated at 6. The discharge electrodes 4 may be supported by framemeans 7 which is mounted on insulators 9. Any other suitableconstruction of electrodes and of support may, however, 'be

used; for example, the collecting electrodes 3 may be formedas plates orscreens on as a series of chains, wires, or other flexible membersspaced sufliciently close to produce approximately the efl ect of acontinuous con- I'BJIIB 11168113 ducting surface; and the discharge electing off the draft or gas flow on the pre-- cipitator, it is desirableto provide for shaking, agitating or rapping the electrodes by meansoperating outside of the precipitating flue. For this purpose, thecollecting electrode frames'above described may be provided with anvils10 projecting through the wall of the flue, for example, through theroof thereof and similarly the discharge electrode frames may beprovided with anvils 11 projecting through the roof of the flue,suitable insulation indicated at 8 being provided where these anvilsfrom the discharge electrodes pass through the roof. If it is desired toclean the precipitator by manual operation, the operator will pass overthe flue, striking the anvils l0 and 11 for each section so as to jarthe collecting and discharge electrodes in such section and will passfrom section to section so as to operate upon the-electrodes of theseveral sections successively. In this operation most of the materialdislodged from the electrodes of any one section will fall into thereceiving means or hoppers indicated at 5, at the bottom of the flue. Inthis connection, it may be stated that the material which has beenprecipitated and which is dislodged on shaking is generally conglom:erated into larger masses than the original dust and fume content in thegases thus minimizing the tendency for the material to pass along withthe gas stream. In general, however, more or less of such dislodgedmaterial particularly the finer particles thereof'will be carriedforward with the gas stream and Will be collected in succeeding sectionsof the precipitator. It may also be stated that in electricalprecipitating apparatus of'this nature, including a series of sectionsoperating successively on the gas stream, the major portion of thesuspended material is caught in the first few sections.

and the last sections of the precipitator only serve to perform a finalclean-up and receive but little material so that in cleaning such lastsections, the material which may pass therefrom and fail to be caught ina succeeding section is a relatively .small amount.

I prefer to provide for automatic operation of the cleaning means sothat the expense of manual control or operation of the apparatus isreduced to a" minimum. For this purpose an operating shaft 13 may beprovided extending above the flue 1 and aoove the respective sections ofthe precipitatorv above described, said shaft carrying cams 14: adaptedto operate upon trip hammers 15 which are mounted on a suitable pivotalsupport 16 and are adapted to strike anvil means 10 on the collectingelectrode and anvil means 11 on the discharge electrode.

A control shaft 18 is also provided carrying a series of cams 19 whichnormally engage projections 20 on the respective trip hammers 15 to holdthe same out of engagement with the operating cams 14. When the notch ordepressed portion of any cam 19 comes opposite the projection 20 for thecorresponding trip hammer, such trip hammer is lowered into position foroperation thereof by the cam means 14; the severalcams 19 being sopositioned as to bring the series of trip hammers 15 successively intooperation and show that the cleaning r operation progresses along thetreater from section'to section and is repeated indefinitely in a cyclicmanner. In case it is desired to cut off the current during the cleaningoperation, this may be effected by switch means controlled, for example,by the control shaft 18. Thus, the cams 19 on said shaft may operateswitch levers 22 for making connections between contacts 23 and 24connected respectively to an electrical supply circuit-25 and (by wire26) to the high tension discharge electrodes of the sectioncorresponding to said cam, there being a switch 22 for each section orunit of the circuit during the operation of the cleaning means therein.

Suitable circuit connections are made for supplying the electricalprecipitator with the unidirectional current of high potentialdifference, such connections including, for

example, a rectifier of suitable type connect-' ply transformer, Fig. 5showing diagram,

matically circuit connections suitable for this purpose, 26 indicatingthe supply lines leading to the discharge electrodes for the respectivesections, 28 indicating a suitable rectifier such as a mechanicalrectifier, or a valve rectifier such as a kenotron, said rectifier beingconnected to the secondary of a high tension transformer, which isprovided with aground connection indicated at 29. The primary winding 30of each of said transformers may be connected at one Side treater sothat each section is shut off in the to an alternating current supplyline indicated at 32 and at the other side to one'of a series ofcontacts 33 adapted to be engaged by contact means 34 on'the controlshaft 18 aforesaid, said contacts 34 being so positioned and arranged asto successively in-.

terrupt the primary or energizing circuits for the respectivetransformers and to shut oil the supply of electrical energy toeachconstruct-ion extending transversely of the flue 37 and formed, forexample, of vertical Wires or chains, spaced sufliciently close togetherto produce approximately the effect of a substantially continuoussurface, and the high tension discharge electrodes 38'being formed aswires, chains, or 'rods of a small cross section spaced sufiicient-lyfar apart to facilitate electrical discharge therefrom and suspendedfromframes supported 'on insulators 39. In this case the gas to becleaned passes successively through the discharge electrodes andcollecting electrodes and provision is made for successive cleaning ofthe sets of discharge and receiving electrodes; for example, by means ofhammer devices 40 and 41 res ectively for the discharge electrodes andthe collecting electrodes, said hammer devices beingcarried by levers 42mounted on pivot or shaft 43 andoperated by cam means 44 on a shaft 45rotated in any suitable manner. In the rotation of said'shaft thelevers, 42 are successively operated ,so as to raise the correspondinghammer devices 'which are allowed to fall suddenly into contact with therespective electrodes, In the operation of this form of my invention thegas stream passes successively through the series of discharge andcollecting electrodes and is subjected tot-he action of electrical fieldmaintained between said electrodes in such manner as to cause electricalprecipitation of suspended material onthe electrodes, such suspendedmaterial being removed from the electrodes by successive operation ofthe cleaning means on the respectlve electrodes,

only one or a limited number of electrodes being cleaned at any onetime, and the material dislodged therefrom falling into the collectingmeans 48 at the bottoni'of the flue 37 or being collected onsucceedingelectrodes'a's the case maybe.

My invention may be carried out n such manner as to provide for clean ngofthe recipitator sections while the potential diference is maintainedbetween the electrodes thereof, the cleaning means shown in Figs.

3 and 4 being suitable for the purpose, su'itable insulation, indicatedat 46, being provided for the hammer devices for the high tensionelectrodes.

What I claim is: 1. The method of removing suspended material from gaseswhich consists in subjecting a gas stream to the action of a series ofelectrical fields, each of said fields be in produced by a separate setof discharge an collecting electrodes, and cleaning electrodes of eachset indpendently of the other sets without'interruption of the gasstream.

2. The method of removing suspended so I material from gases whichconsists in subjecting a gas stream to the action ofa series ofelectrical fields, each of said fields bein produced by ,a separate setof discharge an collecting electrodes, and cleaning both the dischargeand collecting electrodes of each set independently of the other setswithout interruption of the gas stream.

3. The method of removing sus ended material from gases which consistsin subjecting the gas stream to the action of, a series of electricalfields, each of said fields being maintained between discharge andcollecting electrodes, and subjecting the said electrodes for therespective electrical fieldsto cleaning action successively withoutinterruption of the gas stream, the electrical connection to theelectrodes of each of the electrical fields being interrupted during thecleaning operation thereon;

4. An apparatus for electrical precipitation of suspended materialfromgases comprising a series of precipitatin sections eachconiprising aseparate set 0 opposin electrodes, and means for maintaining saiopposing electrodes at high potential difference and cleaning meansadapted to operate on electrodes of each set independent-1y of the othersets of the electrical precipit-ator, while the gas flow is maintainedthrough such. sections, the number of sections being sufiicient toenable effective precipitation of suspended material from the gases bythe operation of the electrical precipitator as awhole during each ofsuch cleaning operations.

5. An apparatus for electrical precipitation of suspended material iromgases comprising, a series of precipitating sections each comprisingopposing electrodes, and means for maintaining said opposing elec trodesat high potential difierence, cleaning means adapted to operatesuccessively on the successive sections of the electrical recipit-ator,while-the gas flow is maintained through such sections, the number ofsec tions being suflicient to enable efi'ective precipitation ofsuspended .material from the gases by the o eration of the electricalprecipitatoras a w ole during each of such cleaning operations, and.means for interrupting the supply of electric current to each of suchsections during the cleaning thereof. g

6. The method of removing suspended material from gases which consistsin cansing such gases to flow horizontally through a series of electricfields maintained between vertically extending electrodes and subjectingthe said electrodes for the respective electrical fields to cleaningaction successively without interruption of the gas stream.

7. The method as set forth in claim 6 and comprising in additioninterrupting the 15 In testimony whereof I have hereunto subscribed myname this 22nd day of May, 20

EVALD ANDERSON.

